09-01-2015
Eran
Calcite | Level 5
Member since
09-18-2012
- 4 Posts
- 0 Likes Given
- 0 Solutions
- 0 Likes Received
-
Latest posts by Eran
Subject Views Posted 1249 02-11-2013 08:00 AM 1962 09-22-2012 01:49 PM 1962 09-19-2012 01:52 PM 2093 09-18-2012 01:05 PM -
Activity Feed for Eran
- Posted Constraining the correlation of two random effects in proc MIXED on Statistical Procedures. 02-11-2013 08:00 AM
- Posted Re: Constrain a fix effect in porc mixed on Statistical Procedures. 09-22-2012 01:49 PM
- Posted Re: Constrain a fix effect in porc mixed on Statistical Procedures. 09-19-2012 01:52 PM
- Posted Constrain a fix effect in porc mixed on Statistical Procedures. 09-18-2012 01:05 PM
02-11-2013
08:00 AM
Hi all, Does anybody know how I can constrain the correlation between two random effect to be 1? I know about the PARMS statement (with the hold option), but with this statement I can constrain the Co-variance, but is there a direct way to constrain the correlation itself? Thanks a lot Eran.
... View more
09-22-2012
01:49 PM
Hi Ivm thank you very much for the detailed answer..... it helps me a lot. Another thing, with the ML approach can I compare a model with only positive event as predictor to a model with positive event and negative event as predictors (with the X square distribution with 1 [in case of only added fix effect] or 2 [in case of random and fix effect] degree of freedom ? and lastly, is the difference between the random and the repeated statement that the random statement models the between subject random effect (e.g,. how positive event is associated differently with mood for each subject) and the repeated statement models the within person variation? Again, thanks a lot Eran
... View more
09-19-2012
01:52 PM
I will try to be more specific Let's say that I have a diary data from several subjects. That is my data has a structure of days nested within persons. Let's say that my hypothesis is that daily mood will be predicted by daily positive and negative events. So I want to use multi-level models analyses (MLM/HLM) with proc mixed to test my hypotheses. My model would be something like this level 1: MOODjt= b 0j + b 1j *positive event + b 2j* negative event + e ij (j=person j, t=day t) And the level 2 (random) of the model would be- Level 2: b 0j = γ 00 + u oj b 1j = γ 10 + u 1j b 2j = γ 20 + u 2j To test this model I would use the following proc mixed syntax proc mixed covtest data=X; class id day; model mood= positive_event negative_event/s ; random intercept positive_event negative_event/subject = id; repeated day/subject = id type = ar(1); run; my question is if I want to constrain the positive_event and Negative_event to have the same weights (let's say of 1) in order to test if they are different from each other (that is, if the constrained model has less fit than the unconstrained model), how can I do that? Put it more simply, if I want that a certain fix effect will have specific value in order to test how it influences the fit of the model, how can I do it? Thanks a lot Eran
... View more
09-18-2012
01:05 PM
Hi all, I'm trying to figure out how to constrain one/few fix effect in proc mixed? Do anybody know how/if I can do that? Thanks Eran
... View more